The present invention relates to thermal treatment apparatus for thermally treating selected tissues of a subject. The invention is particularly useful as a thermal treatment apparatus for treating prostate, bladder and uterus, and is described below particularly with respect to an apparatus for treating the prostate. The invention also relates to a catheter construction, a heater, a peristaltic pump, and a thermal sensor assembly, all especially useful in the novel thermal treatment apparatus.
Thermal treatment is now a recognized form of treatment of certain types of ailments including benign prostatic hyperplasia (BPH), prostatitis, and prostate cancer. My prior U.S. application Ser. No. 07/669,366, filed Mar. 14, 1991, now U.S. Pat. No. 5,257,977 discloses one form of thermal treatment apparatus including a catheter insertable into the subject""s urethra. The proximal end of the catheter includes an inflatable anchoring section in the form of a balloon to be anchored in the subjects bladder, and a heating section which, when the balloon is so anchored, extends through the subject""s prostate. A heated liquid, such as water, is used to inflate the balloon and is also circulated through the heating section to heat the adjacent tissues of the prostate and the bladder neck.
The present invention relates to this type of thermal treatment apparatus but provides a number of important advantages, as will be described more particularly below.
According to the present invention, there is provided a thermal treatment apparatus for thermally treating selected tissues of a subject located in or near a body cavity, comprising a catheter insertable into the subject""s body cavity and including a proximal end formed with an inflatable anchoring section for anchoring the catheter in the body cavity, a distal end to be located externally of the body cavity, and an inflatable heating section adjacent the proximal end to be located near the tissue to be heated. The catheter is formed with first and second passageways extending from the distal end to the, inflatable heating section for circulating heated fluid through the inflatable heating section but not through the inflatable anchoring section; and a third passageway from the distal end to the inflatable anchoring section for inflating the inflatable anchoring section with a non-heated fluid, whereby the inflatable heating section and the tissue in its proximity may be heated to a desired high temperature without correspondingly heating the inflatable anchoring section and the tissue in its proximity.
By thus inflating the anchoring section at the proximal end of the catheter with a separate, non-heated fluid, the heating fluid may be more particularly targeted, by the inflatable heating section, to the tissue to be subjected to the thermal treatment, thereby enabling higher temperatures to be applied if desired.
According to a another aspect of the invention, there is provided a thermal treatment apparatus for thermally treating selected tissues of a subject located in or near a body cavity, comprising: a catheter insertable into the subject""s body cavity and including a proximal end having an inflatable anchoring section for anchoring the catheter in the body cavity, a distal end to be located externally of the body cavity, and an inflatable heating section adjacent the proximal end to be located near the tissue to be heated; first and second passageways from the distal end to the inflatable heating section for circulating heated fluid through the inflatable heating section but not through the inflatable anchoring section; a first thermal sensor assembly near the inlet end of the first passageway for measuring the temperature of the heated fluid entering the first passageway; and a second thermal sensor assembly near the outlet end of the second passageway for measuring the temperature of the heated liquid exiting from the second passageway.
More particularly, each of the two thermal sensor assemblies includes: a thermal sensor, a metal tube connectable to the respective end of the respective passageway of the catheter to receive the heated fluid flowing therethrough; a metal thermal coupling member formed with a recess on one face for receiving the thermal sensor therein, a recess on the opposite face complementary to the shape of the metal tube for receiving the metal tube therein, and a relatively thin web between the two recesses; and a cover pressing the metal tube to the metal thermal coupling member.
According to a still further aspect of the invention, there is provided a liquid heater which is particularly useful in such thermal treatment apparatus and including a heating block formed with a semi-spherical cavity; a container defining a liquid reservoir and also formed with a semispherical wall removably receivable in the cavity of the heating block; a cover attached to the container; a liquid inlet tube passing through the cover for inletting a liquid into the container to be heated by the heating block; and a liquid outlet tube passing through the cover for outletting a liquid from the container after having been heated by the heating block.
According to a further aspect of the invention, there is provided a peristaltic pump particularly useful in thermal treatment apparatus, which peristaltic pump includes a housing formed with a cylindrical cavity; and a rotor rotatably mounted within the cavity and carrying rollers engageable with a peristaltic tube insertable into the cavity for pressing the peristaltic tube against a wall of the housing in order to pump a liquid through the peristaltic tube during the rotation of the rotor; the wall of the housing including a skirt depending from a lid removably received over the cylindrical cavity; the depending skirt extending less than the circumference of the lid to produce an interruption in the housing wall against which the peristaltic tube is pressed by the rollers of the rotor.
Further features and advantages of the invention will be apparent from the description below.